A Difference-In-Differences Analysis of New Persistent Opioid Use After Surgery

In the United States, surgical care has become a gateway for chronic opioid dependence and its associated morbidity. Between 5-10% of patients who receive opioids for postoperative pain control go on to develop long-term opioid use. This translates to more than 2 million previously opioid-naïve individuals developing chronic opioid use after surgery each year. Persistent opioid use after surgery is associated with increased readmissions, healthcare utilization, and healthcare expenditures. Critically, long-term opioid use increases the risk of overdose and death in patients who, prior to their surgery, had no exposure to opioids.

Growing recognition of this problem has led to numerous efforts aimed at reducing opioid-associated morbidity after surgery. These include legislative limits on opioid prescribing for acute pain, procedure-specific prescribing guidelines based on patient-reported opioid use, and opioid-sparing pain management pathways. In Michigan specifically, the Michigan Opioid Prescribing and Engagement Network (M-OPEN) led a statewide quality improvement effort beginning in 2016 that focused on provider education using evidence-based opioid prescribing guidelines. Previously, these guidelines have been shown to significantly reduce excessive postoperative opioid prescribing across the state, however it is currently unknown whether these efforts have had any effect on the actual incidence of persistent opioid use after surgery.

Therefore, the current study will evaluate the incidence of new persistent opioid use before and after the establishment of M-OPEN in Michigan. Beginning in 2016, a statewide quality improvement initiative was undertaken in Michigan to improve postoperative opioid prescribing. In order to accomplish this goal, this study will use a difference-in-differences approach to compare new persistent opioid use in Michigan before and after 2016 to other states where no such quality improvement effort existed.

Inclusion criteria

• Adult patients (18 years and older)
• Patients undergoing one of the following procedures: laparoscopic cholecystectomy, laparoscopic appendectomy, minor hernia repair (including laparoscopic or open inguinal, femoral, umbilical, and epigastric hernia repair), open and laparoscopic ventral/incisional hernia repair, laparoscopic colectomy, open colectomy, vaginal hysterectomy, laparoscopic hysterectomy, and open abdominal hysterectomy
• Patients who underwent surgery between January 1, 2013 and December 31, 2019

Exclusion criteria

• Patients who are not opioid-naive at the time of surgery, defined as filling 1 or more opioid prescriptions between the 12 months to 31 days prior to surgery
• Patients without continuous insurance enrollment for at least 12 months before and at least 6 months after the date of surgery
• Patients still in the hospital on postoperative day 30
• Patients not discharged home after surgery
• Patients who underwent another surgery within 6 months of their index operation